How Walnuts Are Grown

It's a long road from planting a walnut orchard to delivering fresh, delicious walnuts to your local market. Find out about the process from tree to table, and the strict food quality and safety standards that regulate the walnut industry.

Each step in the process from propagation, to harvest, to packer, and finally to market is handled with care and attention. There are over 4,000+ walnut growers, a large majority being family farms, many of which have been in the walnut business for several generations.

Walnut production takes commitment and patience, and orchards are dedicated only to walnut production. After a walnut sapling is planted, it takes five to seven years for it to grow into an adult tree suitable for harvesting. Although many varieties of walnuts are grown in California, six varieties account for over 85%: Chandler, Hartley, Howard, Tulare, Serr, and Vina.

Harvesting

Harvesting begins in late August, when the drying green hulls start to split (allowing the inshell walnuts to be removed), and continues until late November. First, the orchard floor is swept clean. Then, mechanical shakers vigorously shake each tree and thousands of walnuts fall to the ground. The walnuts are carefully swept into windrows to allow mechanical harvesters to pick them up for cleaning.

Processing

The outer green husk is removed by a huller and the nut is mechanically dehydrated (air-dried) to the optimum 8% moisture level. This prevents deterioration of the nut and protects its quality during storage. Walnuts are stored until needed for cracking. California walnuts are protected from contamination because of the nut's double envelope of hull and shell while on the tree.

Walnut Packing

Walnuts are transported to a packing plant where they are graded into two distinctive markets, inshell and shelled.

Inshell Walnuts

Following drying, sizing of the inshell nut occurs. Inshell walnuts are sized as jumbo, large, medium, or baby according to USDA standards.

Shelled Walnuts

Walnuts for both consumer and industrial use are removed from storage as needed and sent to the shelling department where they are mechanically cracked. The shelled material is screened. Kernels are screened into a series of sizes, air-separated from shells, and moved through electronic color graders and shell sorters.

Finally, they are hand-sorted by trained sorters and certified by for quality and USDA standards; then, they are ready for packing.

Once shelled, walnut kernels are physically inspected to ensure an end product that is clean, well-dried, and of specified color, as determined in comparison to the official walnut color chart.

Tolerances for total and special defects are specified for each grade. Laboratory tests, both chemical and microbiological, are conducted to meet strict regulatory agency and food safety requirements.

California Walnuts Meet Strict Quality Control Standards

California walnuts are produced under stringent quality controls that exceed California inspection standards, reputed to be the world's toughest. Handlers also meet individual customers' standards and specifications. Many cutting-edge technologies are harnessed during the process in a sustained effort to bring consumers walnuts of uncompromising quality.

The walnuts are grown and processed under the strict regulation of the California Walnut Board, USDA/DFA and the US Food and Drug Administration (FDA). A food safety control program and quality control regime (HAACP) is in place that meets the standards imposed by all regulatory authorities.

Packaging

California walnuts are produced in a wide variety of sizes, color grades and combinations of sizes and colors to meet the specifications of any industrial formulation. Commercial product meets the same high standards of quality as those sold directly to the consumer.

About Us

The California Walnut Board was established in 1948 to represent the walnut growers and handlers of California. The Board is funded by mandatory assessments of the handlers.The California Walnut Commission, established in 1987, is funded by mandatory assessments of the growers.

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Supportive but not conclusive research shows that eating 1.5 ounces of walnuts per day, as part of a low saturated fat and low cholesterol diet, and not resulting in increased caloric intake may reduce the risk of coronary heart disease. U.S. Food and Drug Administration, March 2004.

One ounce of walnuts provides 18g of total fat, 2.5g of monounsaturated fat, 13g of polyunsaturated fat, including 2.5g of alpha–linolenic acid — the plant-based omega–3.